This invention relates to a transformer with a rectifier used chiefly with a resistance welding machine.
As for a transformer of this kind, an example of a known type, as shown in FIG. 1, has a transformer main body, having therein a primary coil and a secondary coil, and is provided at its front surface with a secondary electrode plate a connected to the secondary coil, and the electrode plate a is provided at its front surface with a terminal plate c connected through a rectifier b, and the two plates a, c are fastened together by means of bolts d or the like. It is common with this type of transformer that the rectifier b is of the type that, as shown in the same Figure, a semiconductor element b.sub.1 is encased in a casing e comprising front and rear electrode covers e.sub.1, e.sub.1 and a circumferential seal ring e.sub.2 is held between the two covers e.sub.1, e.sub.1. The semiconductor element b.sub.1 is also held in the casing e between the mutually facing surfaces of plates a, c. This conventional structure, however, is inconvenient in that the casing e causes the rectifier b to become comparatively large in thickness, and thereby the transformer apparatus is required to have a greater length as a whole. Additionally, it is inconvenient because when a sputtering operation is carried out, the peripheral portions of the two covers e.sub.1, e.sub.1 may be covered with sputtered material, likely resulting in a short-circuit between the two covers e.sub.1, e.sub.1 and accordingly between the two plates a, c.